Extractor and related methods

ABSTRACT

An extractor suitable for using a solvent to separate a compound from a solid or semisolid substance containing the compound. The extractor includes a conveying assembly having an inclined conveyor for receiving the substance from a substance inlet and moving the substance through the solvent, an inclined upper surface associated with the first conveyor and an inclined lower surface associated with the first conveyor. The conveyor is configured to move the substance downward through the solvent along the upper surface toward a lower end of the conveyor and upward through the solvent along the lower surface toward an upper end of the conveyor.

FIELD OF THE INVENTION

The present application generally relates to extractors and, moreparticularly, to counter-current solvent extractors.

BACKGROUND OF THE INVENTION

Solvent extraction is a method for separating a compound or substancefrom one or more other compounds or substances by using one or moresolvents. This method is used in industry, and in the laboratory forrefining, isolating and purifying a variety of compounds such as oilfrom seeds. In liquid-liquid extraction, the compound to be extracted isdissolved in a liquid and a liquid solvent is used for the extraction.The process relies on variations in the solubilities of differentcompounds in different substances. The method may also be applied tosolid materials that contain compounds that need to be extracted.Generally, the solvent used dissolves the compound leaving behind thesolid material that contained it.

SUMMARY OF THE INVENTION

A first exemplary embodiment is directed to an extractor suitable forusing a solvent to separate a compound from a solid or semisolidsubstance containing the compound. The extractor includes a conveyingassembly having an inclined conveyor for receiving the substance from asubstance inlet and moving the substance through the solvent, aninclined upper surface associated with the first conveyor and aninclined lower surface associated with the first conveyor. The conveyoris configured to move the substance downward through the solvent alongthe upper surface toward a lower end of the conveyor and upward throughthe solvent along the lower surface toward an upper end of the conveyor.

In another exemplary embodiment, the extractor includes a plurality ofconveying assemblies arranged in series. Each conveying assemblyincludes an inclined conveyor for receiving the substance from asubstance inlet or a preceding conveying assembly and moving thesubstance through the solvent, an inclined upper surface associated withthe respective conveyor and an inclined lower surface associated withthe respective conveyor. Each conveyor is configured to move thesubstance downward through the solvent along the respective associatedupper surface toward a lower end of the conveyor and upward through thesolvent along the respective associated lower surface toward an upperend of the conveyor.

In another exemplary embodiment, the extractor includes an inclinedscreen section forming a portion of an inclined lower surface. Theconveyor being configured to move the substance upward across theinclined screen surface to allow solvent to drain from the substance.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become apparent tothose of ordinary skill in the art to which the invention pertains froma reading of the following description together with the accompanyingdrawings, in which:

FIG. 1 is a schematic illustration of an exemplary embodiment of anextractor;

FIG. 2 is a schematic illustration of the extractor of FIG. 1 with theportions of the conveying assemblies removed;

FIG. 3 is an enlarged view of a conveying assembly of the extractor ofFIG. 1; and

FIG. 4 is a top view of a conveyor of the extractor of FIG. 1;

DETAILED DESCRIPTION

As described herein, when one or more components are described as beingconnected, joined, affixed, coupled, attached, or otherwiseinterconnected, such interconnection may be direct as between thecomponents or may be indirect such as through the use of one or moreintermediary components. Also as described herein, reference to a“member,” “component,” or “portion” shall not be limited to a singlestructural member, component, or element but can include an assembly ofcomponents, members or elements. “Physical communication” as usedherein, includes but is not limited to connecting, affixing, joining,attaching, fixing, fastening, placing in contact two or more components,elements, assemblies, portions or parts. Physical communication betweentwo or more components, etc., can be direct or indirect such as throughthe use of one or more intermediary components and may be intermittentor continuous.

FIG. 1 illustrates an exemplary embodiment of an extractor 100configured to a hold volume of one or more solvents suitable to separatea compound from a solid or semisolid substance containing the compound.While the extractor 100 of FIG. 1 is illustrated as including sixconveying assemblies arranged in series, it should be understood thatextractors within the scope of the present disclosure may includerelatively fewer conveying assemblies or relatively more conveyingassemblies, as further described herein. The extractor 100 includes oneor more mechanisms configured to move the substance through the solvent.The extractor 100 may be suitable for separating a variety of compoundsfrom a variety of solid or semisolid substances. For example, thesubstance and compound may be or may include plant matter. The compoundmay be rubber and the substance may be non-Hevea plant matter. Thecompound may be rubber and resin and the substance may be non-Heveaplant matter. As used herein the term “plant matter” means materialobtained from a non-Hevea plant. Unless otherwise specified, the plantmatter may include one or more of roots, stems, bark, woody material,pith, leaves and dirt. In certain embodiments, the extractor 100 issuitable for separating rubber from plant matter, or suitable forseparating rubber and resin from non-Hevea plant matter. As used hereinthe term “resin” means the naturally occurring non-rubber chemicalentities present in non-Hevea plant matter, including but not limited toresins (such as terpenes), fatty acids, proteins, and inorganicmaterials. As used herein, the term non-Hevea plant is intended toencompass plants that contain natural rubber within the individual cellsof the plant. In certain embodiments, the non-Hevea plant matter is fromone or more of the following: Parthenium argentatum (Guayule shrub),Taraxacum Kok-Saghyz (Russian dandelion), Euphorbia lathyris (gopherplant), Parthenium incanum (mariola), Chrysothamnus nauseosus(rabbitbrush), Pedilanthus macrocarpus (candililla), Asclepias syriaca,speciosa, subulata, et al (milkweeds), Solidago altissima, graminifoliarigida, et al (goldenrods), Cacalia atripilicifolia (pale Indianplantain), Pycnanthemum incanum (mountain mint), Teucreum canadense(American germander) and Campanula Americana (tall bellflower). Incertain embodiments, the extractor 100 is suitable for use with guayuleplant matter. In one exemplary embodiment, the extractor is configuredto be suitable for separating natural rubber from guayule biomass. Asused herein the term “biomass” is used to refer to the portion of groundor chopped plant matter from a non-Hevea plant that is insoluble and,hence, is suspended rather than dissolved by organic solvents. As usedherein, biomass should be understood to include a certain amount of dirtand ash, unless otherwise specified.

While the phrases “a compound” or “the compound” are used herein torefer to what is separated from the solid or semisolid substance, itshould be understood that the term can be used to refer to one or tomore than one compound that is separated. Likewise, while the phrases “asolvent” or “the solvent” are used herein, it should be understood thatthe phrases encompass not only one solvent but also more than onesolvent (e.g., two solvents, three solvents, or more).

Generally, a variety of one or more solvents may be used to separate thecompound from the solid or semisolid substance. Depending on theparticular application, particular compound sought to be separated, andparticular substance from which the separation is made, any suitablesolvent may be used with the extractor. Generally, at least one solventwill be used and that solvent will be suitable for solubilizing (andhence extracting) the compound from the solid or semisolid substance. Inthose embodiments where two compounds are sought to be separated (e.g.,rubber and resin), generally two solvents will be utilized, with thefirst compound being more soluble in one solvent and the second compoundbeing more soluble in the other solvent. In certain embodiments, thesolvent comprises water. In certain embodiments, the solvent comprisesone or more organic solvents; in certain such embodiments, the solventcomprises at least one polar organic solvent and at least one non-polarorganic solvent. A polar organic solvent will preferentially solubilizeresin and a non-polar organic solvent will preferentially solubilizerubber. In certain embodiments, the at least one polar organic solventis selected from alcohols having 1 to 8 carbon atoms (e.g., ethanol,isopropanol, ethanol and the like); ethers and esters having from 2 to 8carbon atoms; cyclic ethers having from 4 to 8 carbon atoms; and ketoneshaving from 3 to 8 carbon atoms (e.g., acetone, methyl ethyl ketone andthe like); and combinations thereof. In certain embodiments, the atleast one polar organic solvent comprises or is acetone. In certainembodiments, the at least one non-polar organic solvent is selected fromalkanes having from 4 to 9 carbon atoms (e.g., pentane, hexane,heptanes, nonane and the like); cycloalkanes and alkyl cycloalkaneshaving from 5 to 10 carbon atoms (e.g., cyclohexane, cyclopentane andthe like); aromatics and alkyl substituted aromatics having from 6 to 12carbon atoms (e.g., benzene, toluene, xylene and the like); andcombinations thereof. In certain embodiments, the at least one non-polarorganic solvent comprises or is: hexane, cyclohexane, or a combinationof both.

Referring to FIGS. 1 and 2, the extractor 100 includes a housing 102.The housing 102 can be configured in a variety of ways and constructedfrom a variety of materials. For example, the shape and size of thehousing 102 may vary in different embodiments and the housing may beconstructed from any materials suitable for the particular applicationand solvent being used. For example, the housing 102 may be constructedfrom a metal, such as stainless steel or carbon steel, which issufficiently resistant to corrosion by a particular solvent. Inaddition, one or more coatings can be applied to the interior, theexterior, or both, of the housing surfaces to prevent damage caused bythe solvent.

In the depicted embodiment, the housing 102 is generally an elongatedbox-shape having a first end wall 104 and a second end wall 106 that isspaced apart from and generally parallel to the first end wall. A bottomwall 108 extends from the first end wall 104 to the second end wall 106.A top wall or lid 110 is spaced apart from and generally parallel to thebottom wall 108. The top wall 110 extends from the first end wall 104 toan inclined neck section 112 connecting the top wall 110 to the secondend wall 106. The housing 102 also includes a first side wall (notshown) and a second side wall (not shown) spaced apart from andgenerally parallel to the first side wall. The first side wall and thesecond side wall extend horizontally from the first end wall 104 to thesecond end wall 106 and extend vertically from the bottom wall 108 tothe top wall 110.

The housing 102 forms a tank or internal chamber 114 configured to holdboth the solvent and the mechanisms for moving the substance through thesolvent. The tank 114 may be configured in a variety of ways, includingvarious shapes and sizes. In the depicted embodiment, the tank 114includes a floor 116 having one or more recesses 118. It should beunderstood that the extractor will generally include a number ofrecesses commensurate with the number of conveying assemblies. Each ofthe one or more recess 118 has a first floor portion 120 and a secondfloor portion 122 extending traverse to the first floor portion. In thedepicted embodiment, the second floor portion 122 extends atapproximately a 90 degree angle to the first floor portion 120. In otherembodiments, however, the second floor portion 122 may extend at anangle greater than or less than approximately 90 degrees to the firstfloor portion 120. The first floor portion 120 and the second floorportion 122 are connected by curved corner 124 having a radius R₁. Thefirst floor portion 120 inclines upward from the corner 124 generallytoward the first side wall 106 and the second floor portion 122 inclinesupward from the corner 124 generally toward the second side wall 106.

The inclined neck section 112 includes an inclined screen section 126forming a least a portion of the floor of the inclined neck section 112.The inclined screen section 126 may be formed in a variety of ways. Anyporous structure capable of allowing solvent to drain from the substancemay be used. In the exemplary embodiment, the inclined screen section126 includes a metal wedge wire screen 128 and has a length L_(s). Belowthe inclined screen section 126 is an inclined catch surface 130configured to divert solvent back to a tank or internal chamber 114. Theinclined screen section 126 includes an upper terminal end 132.

The extractor 100 may include one or more inlets and one or more outletsfor the solvent and for the solid or semi-solid substance to enter andexit the extractor. The number, configuration, and location of the oneor more inlets and outlets for the solvent and the substance can vary indifferent embodiments of the extractor. While an inlet or an outlet maybe described as a solvent inlet, a solvent outlet, a substance inlet ora substance outlet, that description is not meant to be limiting. Forexample, during operation of the extractor, the substance and thesolvent necessarily mix and the substance exiting the extractor 100 maybe laden with solvent while the solvent exiting the extractor 100 mayhave particles of the substance suspended in the solvent. Likewise, theexiting solvent and substance may be recycled and reintroduced into theextractor for further processing.

In the depicted embodiment, the extractor 100 includes a first solventinlet 134 located in the neck section 112 of the extractor 100. Thefirst solvent inlet 134 includes one or more nozzles 136 directed tospray solvent in a generally downward direction over the inclined screensection 126 where the inclined catch surface 130 diverts that solventinto the tank 114. The extractor 100 includes a first solvent outlet 138located in the first side wall 104 at a height H₁ above the bottom wall102. The height H₁ of the first solvent outlet 138 can be used to setthe level of solvent in the tank 114 as depicted by the dashed line 140in FIG. 1. Optionally, the extractor 100 may include additional solventsinlets and outlets. For example, in one exemplary embodiment, theextractor 100 includes a second solvent inlet 141 located in the necksection 112. The second solvent inlet 141 may be configured in a similarmanner to the first solvent inlet 134 to spray solvent in a generallydownward direction over the inclined screen section 126, though otherconfigurations are possible. In one exemplary embodiment, the firstsolvent inlet 134 is configured to spray new solvent into the extractor100 and the second solvent inlet 141 is configured to spray recycled orrecovered solvent into the extractor.

The extractor 100 includes a first substance inlet 142 for introducing,into the extractor, the solid or semi-solid substance containing thecompound to be separated by the solvent. The first substance inlet 142is located in the top wall 110 and configured such that substanceentering the substance inlet will drop vertically downward into the tank114. Optionally, the first substance inlet 142 may be located at adifferent location or additional substance inlets may be provided. Inthe depicted embodiment, a second substance inlet 144 is located in thetop wall 110 and configured similar to the first substance inlet 142such that substance entering the second substance inlet 144 will dropvertically downward. The second substance inlet 144 is positioned closerto the second end wall 106 than the first substance inlet 142. Incertain embodiments, the substance that drops vertically downward from asubstance inlet drops onto a conveying assembly, such as onto the chainof a conveying assembly.

As discussed above, in certain embodiments, the substance comprisesnon-Hevea plant matter, including in certain such embodiments guayuleplant matter. Generally, any non-Hevea plant matter (e.g., guayule plantmatter) entering the extractor will have been chopped or otherwisereduced in size from its natural state. In certain embodiments, theguayule plant matter entering the extractor has an average size of 2inches or less, 1.5 inches or less, or 1 inch or less. The sizereduction of the non-Hevea plant matter may be achieved using variousphysical means, some of which may assist in removing relatively morerubber from the cells of the plant matter. Exemplary apparatus for sizereduction include: a shredder, a granulator, a hammer mill, a rollermill, and combinations thereof.

The extractor 100 includes a first substance outlet 146 located in theneck section 112 adjacent the upper terminal end 132 of the inclinedscreen section 126 and configured to allow the substance to exit theextractor 100. The first substance outlet 146 optionally includesrun-down screen 148. The run-down screen 148 is configured to receivethe substance that has passed through the solvent in the extractor 100and allow the solvent to drain from the substance while the substanceresides on the run-down screen 148. It should be understood thatgenerally only a portion of the solvent associated with the substancewill drain while the substance resides on the run-down screen; in otherwords, when the substance falls off of the run-down screen into thedischarge chute 156, it will not be dry, but will still contain solvent.The run-down screen 148 can be configured in a variety of ways. Anyporous structure configured to allow solvent to drain from the substancemay be used. In the exemplary embodiment, the run-down screen 148 is acurved, static screening component having one or more wedge wire screenpanels 150 with slots (not shown) for slowing drainage of the solvent.The wedge wire panels 150 are fitted within a housing 152 that includesa second solvent outlet 154 under the run-down screen 148 and asubstance discharge chute 156. The housing 152 may be configured in avariety of ways and constructed of a variety of materials. In theexemplary embodiment, the housing 152 is made from stainless steelsheets. The run-down screen 148 has no moving parts and removal of thesubstance from the run-down screen 148 is gravity fed, so the screen isessentially maintenance free.

Referring to FIG. 1, the extractor 100 includes one or more mechanismsfor conveying the substance through the solvent the extractor. The oneor more mechanisms may be configured in a variety of ways. Anymechanism(s) capable of receiving the substance introduced into theextractor 100 and moving the substance through the solvent may be used.In the illustrated exemplary embodiment, the one or more mechanisms areconfigured as a six conveying assemblies 200, though in otherembodiments, more or less than six conveying assemblies may be used. Asshown in FIG. 1, the extractor 100 includes a first conveying assembly202, a second conveying assembly 204, a third conveying assembly 206, afourth conveying assembly 208, a fifth conveying assembly 210, and asixth conveying assembly 212. In certain embodiments, the last conveyingassembly (i.e., the conveying assembly closest the substance outlet) isreferred to as an exit conveying assembly.

Referring to FIGS. 3 and 4, the first conveying assembly 202 includes aconveyor 216, an upper inclined surface 218 associated with theconveyor, and a lower inclined surface 220 associated with the conveyor.The conveyor 216, the upper inclined surface 218, and the lower inclinedsurface 220 may be configured in a variety of ways. In the depictedembodiment, the conveyor 216 is a continuous conveyor having a pluralityof spaced apart paddles 222. The paddles 222 are generally elongated andrectangular having front face 224, a back face 226 generally parallel toand facing in the opposite direction of the front face 224, and an outeredge 227 connecting the front face 224 to the back face 226. Each paddle222 has a height H_(p) and a length L_(p). The shape, height, length,spacing and number of paddles may vary in different exemplaryembodiments of the conveyor 216. The paddles are generally configured toassist in moving the substance along through the extractor, particularlyaround the curved corners (e.g., 234) of the first floor portion andupward along the second floor portion of the recess in which theconveyor is positioned. In preferred embodiments the paddles areflexible or at least comprise a flexible tip portion; flexibility of thepaddles aids in operation of the conveyor, eliminating or at leastminimizing operating difficulties whereby one or more paddles becomeshung-up or stuck with packed solid or semi-solid substance. The paddlesmay be constructed of various materials which are preferablynon-reactive with the substance and the solvent. In certain embodiments,the paddles are plastic, non-limiting examples of which includepolyurethane and polyvinyl chloride.

The paddles 222 are connected to a pair of continuous chains 228, thoughin other embodiments, more or less than a pair of chains may be used.The paddles 222 are attached to the chains 228 by any suitable means. Inthe illustrated embodiment, each paddle 222 is connected to each chain228 by a bracket 230 such that each paddle 222 extends generallyperpendicular from the chains 228. In other embodiments, however, thepaddles 222 may extend from the chains at an angle greater than or lessthan about 90 degrees.

The conveyor 216 includes an upper end 232, a lower end 234 opposite theupper end, an upper side 236 between the upper end 232 and the lower end234, and a lower side 238 beneath the upper side and between the upperend 232 and the lower end 234. The upper end 232 includes a rotatableupper axle 240 onto which a pair of sprockets 242 are fixably mounted.The lower end 234 includes a rotatable lower axle 244 onto which a pairof sprockets 246 are fixably mounted. The chains 228 are configured tomount onto both the sprockets 244 on the upper axle 240 and thesprockets 246 on the lower axle 244 such that rotation of the upper axleand the lower axle will move the paddles 222 along the upper side 236and the lower side 238, and around the upper end 232 and the lower end234.

The conveyor 216 is powered by at least one power source 248. The atleast one power source 248 can be any suitable power source capable ofcausing rotation of the conveyor. In the exemplary embodiment, the atleast one power source 248 includes an electric motor mounted adjacentthe upper axle 240 of each conveyor 216 and configured to rotate theupper axle. Thus, each of the conveyor assemblies 200 includes aseparate power source 248 for powering the conveyor of that assembly. Inother embodiments, however, the power source 248 may power more than oneconveyor assembly.

The upper inclined surface 218 is positioned below the paddles 222 onthe upper side 236 of the conveyor. The upper inclined surface 218extends from the upper end 232 to the lower end 234 of the conveyor 216and has a width (not shown) generally equal to the length L_(p) of thepaddles 222. The upper inclined surface 218 is positioned below thepaddles 222 such that the paddles move adjacent to or engage the upperinclined surface when the conveyor 216 is operating. The upper inclinedsurface 218 can be integral to the conveyor 216 or can be a separatesurface. For example, the upper inclined surface 218 may be a surfaceattached to the housing 102 or may be attached to a portion of theconveyor 216.

The lower inclined surface 220 is positioned below the paddles 222 onthe lower side 238 of the conveyor. The lower inclined surface 220extends from the upper end 232 to the lower end 234 of the conveyor 216and has a width (not shown) generally equal to the length L_(p) of thepaddles 222. The lower inclined surface 220 includes an upper terminalend 250 positioned adjacent the upper end 232 of the conveyor 216. Thelower inclined surface 220 is positioned below the paddles 222 such thatthe paddles move adjacent to or engage the lower inclined surface whenthe conveyor 216 is operating. The lower inclined surface 220 can beintegral to the conveyor 216 or can be a separate surface. For example,the lower inclined surface 220 may be a surface fixably attached to thehousing 102 or may be a surface attached to a portion of the conveyor216. The lower inclined surface 220 can include a portion of the floor116, such as for example, the second floor portion 122.

The conveyor 216 is received within one of the one or more the recesses118 such that the lower end 234 is adjacent the corner 124. When thepaddles 222 rotate around the lower end 234 of the conveyor 216, theouter edge 227 of the paddles 222 is a distance D₁ from a centerline 252of the lower axle 244. The distance D₁ is generally equal to the radiusR₁ of the corner 124 such that the outer edge 227 of the paddles 222generally contact the corner 124 of the floor 116 as the paddles 222move around the lower end 234 of the conveyor 216.

The upper inclined surface 218 is generally parallel to the lowerinclined surface 220. The lower inclined surface 220 may include thesecond floor portion 122 or may be a separate surface. For example, thelower inclined surface 220 may be a separate surface positioned adjacentto and parallel with the second floor portion 122 to form a continuousinclined surface for the paddles 222 to move along. Thus, the paddles222 transition from moving along the second floor portion 122 to movingalong the separate surface. In another exemplary embodiment, the lowerinclined surface 220 may be positioned on top of the second floorportion 122 such that the paddles 222 transition from moving around thecorner 124 to moving along the lower inclined surface 220 withcontacting or minimally contacting the second floor portion 122.

The conveyor 216 has a length L_(c) and a longitudinal axis 253 that isgenerally parallel with the upper inclined surface 218 and the lowerinclined surface 220, thus the conveyor is inclined. In an exemplaryembodiment, the incline angle 254 of the first conveyor assembly 202 isin the range of about 15 degrees to about 35 degrees. In anotherexemplary embodiment, the incline angle 254 is in the range of about 22degrees to about 28 degrees.

The second conveying assembly 204, the third conveying assembly 206, thefourth conveying assembly 208, and the fifth conveying assembly 210 aresubstantially similar to the first conveyor assembly 202 in that theyinclude a conveyor, an associated upper inclined surface, and anassociated lower inclined surface that are arranged and operate in thesame manner as the conveyor 216, the upper inclined surface 218, and alower inclined surface 220 of the first conveying assembly 202. Inaddition, the second conveying assembly 204, the third conveyingassembly 206, the fourth conveying assembly 208, and the fifth conveyingassembly 210 are received in a recess 118 in the floor 116 similar tothe first conveying assembly 204. Therefore, the above descriptionregarding the first conveying assembly 204 applies equally to the secondconveying assembly 204, the third conveying assembly 206, the fourthconveying assembly 208, and the fifth conveying assembly 210.

In the exemplary embodiment of FIG. 2, the second conveying assembly204, the third conveying assembly 206, the fourth conveying assembly208, and the fifth conveying assembly 210 are substantially parallel tothe first conveying assembly 202. Similarly, when the number ofconveying assemblies differs from the number shown in the exemplaryembodiment of FIG. 2, each of those conveying assemblies aresubstantially parallel to each other in certain embodiments. In otherembodiments, however, the conveying assemblies 200 may differ in inclineangle (i.e., be positioned within the extractor at relatively differentincline angles). Likewise, in other embodiments, when the number ofconveying assemblies differs from the number shown in the exemplaryembodiment of FIG. 2, each of those conveying assemblies may differ inincline angle.

The sixth conveying assembly 212 is configured to operate as an exitconveying assembly (i.e. the last conveying assembly 212 prior to thefirst substance outlet 142). The sixth conveying assembly 212 is similarto the first conveyor assembly 202 in that it includes a conveyor 316,an upper inclined surface 318, and a lower inclined surface 320 that arearranged and operate in the same manner as the conveyor 216, the upperinclined surface 218, and a lower inclined surface 220 of the firstconveying assembly 202. In addition, the sixth conveying assembly 212 isreceived in a recess 118 in the floor 116 similar to the first conveyingassembly 204. Therefore, the above description regarding the firstconveying assembly 204 generally applies to the sixth conveying assembly212.

The conveyor 316 of the sixth conveying assembly 212, however, has alength L_(E) that is greater than the length L_(c) of the conveyors ofthe first through the fifth conveying assemblies 202, 204, 206, 208,210. The additional length of the sixth conveyor 316 allows the sixthconveying assembly 212 to extend upward through the neck section 112 ofthe housing, over the inclined screen section 126, to the firstsubstance outlet 146. In one exemplary embodiment, the conveyor 316 hasa length that is approximately 175% to approximately 200% the length ofthe first conveyor. In certain embodiments, the length L_(s) of theinclined screen section 126 is approximately 40% to approximately 55%the length L_(E) of the sixth conveyor 316.

Referring to FIG. 1, in operation, the first, second, third, fourth,fifth, and sixth conveyor assemblies 202, 204, 206, 208, 210, 212 form amulti-stage solvent extracting process, with each conveying assemblyforming an individual stage. The tank 114 of the extractor 100 is filledwith solvent up to the solvent level 140. Solvent in the extractor flowsgenerally from right to left as illustrated in FIG. 1. In particular,solvent is introduced into the extractor 100 by the first solvent inlet134, and optional additional solvent inlets, such as for example, thesecond solvent inlet 141. The first solvent inlet 134, and optionallythe second solvent inlet 141, spray solvent onto the inclined screensection 126 in the neck section 112. The solvent flows through theinclined screen section 126 and onto the inclined catch surface 130. Thesolvent then flows downward along the inline catch surface 130 and intothe tank 114.

The first solvent outlet 138 functions as an overflow. When the solventlevel 140 rises up to the height H₁ of the first solvent outlet 138, thesolvent flows out of the first solvent outlet to maintain the solventlevel in the tank 114. As shown in FIGS. 1 and 3, the solvent level 140is above the upper terminal end 250 of the lower inclined surface 220 ofthe first conveyor assembly 202 and likewise for the other conveyingassemblies 204, 206, 208, 210, 212. Therefore, the solvent introducedinto the extractor 100 at the first solvent inlet 134 has a flow pathover the upper terminal ends of the lower inclined surfaces of theconveying assemblies 200 to the first solvent outlet 138.

It should be understood that the relative level of the terminal ends ofthe lower inclined surfaces as compared to the solvent level, can beadjusted by modifying the solvent level 140 to be higher or lower. Thiscan be accomplished, for example, by blocking solvent flow from thefirst solvent outlet 138 and providing a second solvent outlet 328 (seeFIG. 3) at a height greater than the height H₁ of the first solventoutlet 138.

In the exemplary embodiment, solid or semi-solid substance containingthe compound to be separated is introduced into the extractor 100 abovethe first conveying assembly 202 through the first substance inlet 142.This first substance inlet 142 is positioned above the first conveyingassembly 202 such that the substance introduced into the extractor 100falls downward into the solvent at a position closer to the upper end232 of the conveyor 216 than the lower end 234 of the conveyor.

The substance then settles through the solvent onto the upper inclinedsurface 218 where the substance is engaged by the conveyor 216. Thefirst conveyor 216 is configured to rotate in a counterclockwise manneras illustrated by arrow 330 in FIG. 1. While the primary operation ofthe first conveyor 216 is intended to be counterclockwise, in certainembodiments, the conveyor is reversible so that it may be operated in aclockwise direction; such reverse operation may be useful for limitedperiods of time such as to increase the contact time between the atleast one solvent and the solid or semi-solid substance. The paddles 222of the first conveyor 216 engage the substance and assist in moving thesubstance downward through the solvent along the first upper surface 216toward the lower end 234 of the first conveyor. At the lower end 234,the paddles 222 assist in moving the substance around the corner 124.Since the outer edge 227 of the paddles 222 is at a distance D₁ from thelower axle center line 252 that is generally equal to the radius R₁ ofthe corner 124, the paddles can generally engage the entire surface ofthe corner preventing substance from accumulating in the corner. Oncethe first conveyor 216 moves the substance around the corner 124, thepaddles 222 assist in moving the substance upward through the solventalong the first lower surface 220 toward the upper end 232.

The upper end 232 of the first conveying assembly 202 is positionedabove the second conveying assembly 204. When the substance reaches theupper terminal end 250 of the inclined first lower surface 220, it ismoved beyond the upper terminal end 250 such that substance falls fromthe first lower surface 220 of the first conveying assembly 202 towardthe second conveying assembly 204. The upper terminal end 250 of firstlower surface 220 may be positioned such that the substance falls towardthe second conveying assembly 204 at a position closer to an upper end333 of the third conveying assembly 204 than to a lower end 334, thoughthat is not required.

In the exemplary embodiment of FIGS. 1-4, the upper terminal end 250 ofthe first lower surface 220 is below the solvent level 140. Therefore,when the substance is moved over the upper terminal end 250 and fallstoward the second conveying assembly 204, the substance remains at leastsubstantially constantly immersed in the solvent.

The substance that falls from the first lower surface 220 of the firstconveying assembly toward the second conveying assembly 204 will settlethrough the solvent such that the substance can be engaged by the secondconveyor 342. The second conveyor 342 will then complete similar actionsto the first conveying assembly 202 by moving the substance downwardthrough the solvent along the inclined upper surface 340 of the secondconveying assembly 204, around the corner 124, and upward through thesolvent along the inclined lower surface 344 of the second conveyingassembly 204 before depositing into the solvent above the thirdconveying assembly 206. This process repeats itself until the substancereaches the last (e.g., sixth) or exit conveying assembly 212. While theprimary operation of the conveyor associated with the second conveyingassembly 204, and the conveyors associated with subsequent conveyingassemblies (206, 208, 210 and 212) is intended to be counterclockwise,in certain embodiments, one or more of the conveyors is reversible sothat it may be operated in a clockwise direction; such reverse operationmay be useful for limited periods of time such as to increase thecontact time between the at least one solvent and the solid orsemi-solid substance.

As with the previous conveying assemblies 200, the conveyor 316 of thesixth conveying assembly 212 moves the substance downward through thesolvent along the inclined upper surface 318, around the corner 124, andupward through the solvent along the inclined lower surface 320 of thesixth conveying assembly. While the primary operation of the conveyor316 of the sixth conveying assembly 212, is intended to becounterclockwise, in certain embodiments, the conveyor 316 is reversibleso that it may be operated in a clockwise direction; such reverseoperation may be useful for limited periods of time such as to increasethe contact time between the at least one solvent and the solid orsemi-solid substance. The inclined lower surface 320 associated with thesixth conveying assembly 212, however, at least partially includes theinclined screen section 126. Once the sixth conveyor 316 moves thesubstance above the solvent level 140 and over the inclined screensection 126, at least a portion of the solvent may drain from thesolvent-laden substance through the screen section and onto the inclinedcatch surface 130 to be reintroduced to the tank 114. At the same time,the first solvent inlet 134, and optionally the second solvent inlet141, spray solvent over the substance and the inclined screen section126 as the sixth conveyor 316 moves the substance upward along theinclined screen section.

At the terminal upper end 132 of the inclined screen section 126, thepaddles 222 assist in moving the substance beyond the terminal upper endsuch that the substance falls from the lower inclined surface 320 ontothe run-down screen 148. As the substance collects on the run-downscreen 148, at least a portion of the solvent drains from the substancethrough the screen to the second solvent outlet 154 where it can beremoved from the extractor 100. Over time, the substance passes down thescreen 148 and builds up before eventually falling off the screen underthe force of gravity and into the substance discharge chute 156.

In some exemplary embodiments, the substance is introduced into theextractor 100 above the second conveying assembly 204 instead of thefirst conveying assembly 202. For example, the substance can beintroduced into the extractor 100 through the second substance inlet 144instead of the first substance inlet 142, or alternatively, the firstsubstance inlet 142 may be positioned above the second conveyingassembly 204 instead of the first conveying assembly 202. Alternatively,the first substance inlet is positioned above the second conveyingassembly. Thus, the first conveying assembly 202 is configured to notreceive newly introduced substance. Instead, the first conveyingassembly 202 acts as a clarification assembly positioned between theinlet used for introducing substance to the extractor 100 and the firstsolvent outlet 138. By intentionally not depositing new substance intothe solvent in the area around the first conveying assembly 202, largerparticles of substance suspended in the solvent may settle onto thefirst conveying assembly 202 and be moved through the solvent to thesecond conveying assembly 204 in a similar manner in which the otherconveying assemblies 200 operate.

Solvent that exits the first solvent outlet 138 includes the compoundthat has been extracted from the substance and may also include small(fine) particles of substance. When the solvent that exits the extractorincludes solubilized rubber, it may be referred to as miscella; incertain embodiments, the solvent (or miscella) that exits the extractorcontains solubilized rubber and solubilized resin. Optionally, one ormore separators 400 may be in fluid communication with the first solventoutlet 138 and configured to separate the small particles of substancefrom the exiting solvent. The one or more separators 400 may beconfigured in a variety of ways. Any separator 400 suitable forseparating small particles of the substance from the solvent may beused. For example, the separator 400 may be a centrifuge, a filter, orother suitable separating mechanism. In the exemplary embodiment, theone or more separators 400 include at least one centrifuge. Theseparated substance particles can be reintroduced back into theextractor 100 at the first substance inlet 142, the second substanceinlet 144, or at an additional substance inlet. For example, referringto FIG. 1, an optional third substance inlet 402 is positioned above thefourth conveying assembly 208 and optional fourth substance inlet ispositioned above fifth conveying assembly 210. The separated substanceparticles could be moved from the separator 400 to any suitablesubstance inlet on the extractor 100. It should be understood that theuse of any separator (such as 400) to separate small particles ofsubstance from the solubilized compound in the solvent(s), after thesolvent exits the extractor (such as through first solvent outlet 138)is not in any way essential to the design or operation of the extractordescribed herein.

The substance that exits the extractor 100, such as for example, fromthe first discharge chute 156 of the first substance outlet 146 or anadditional substance outlet, can in certain embodiments be directed toone or more desolventizers 404. The one or more desolventizers 404 aregenerally configured to separate any remaining solvent from the exitingsubstance. The one or more desolventizers 404 may be configured in avariety of ways. For example conventional desolventizing processes,applying principles of steam or heat-stripping or vacuum evaporation maybe used. Non-limiting examples of desolventizing apparatus include, butare not limited to solvent extraction towers, desolventizing screwapparatus. It should be understood that any desolventization of thesubstance that takes place after it exits the extractor is not in anyway essential to the design or operation of the extractor describedherein. However, in practice, disposal of or further use of thesubstance that exits the extractor may practically require removal ofall or substantially all of the solvent contained therein.

In certain embodiments, the solvent separated from the substance by theone or more desolventizers 400 can be recycled and reintroduced into theextractor 100 at the first solvent inlet 134, the second solvent inlet141, or an additional solvent inlet of the extractor 100.

While the present application has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Therefore, the application, in its broaderaspects, is not limited to the specific details, the representativecompositions and processes, and illustrative examples shown anddescribed. Accordingly, departures may be made from such details withoutdeparting from the spirit or scope of the general inventive concept.

What is claimed is:
 1. An extractor suitable for using a solvent toseparate a compound from a solid or semisolid substance containing thecompound, comprising: a substance inlet for introducing the substanceinto the extractor; a substance outlet for removing the substance fromthe extractor; a solvent inlet for introducing the solvent into theextractor; a solvent outlet for removing the solvent from the extractor;and a first conveying assembly including: an inclined first conveyor forreceiving the substance from the substance inlet and moving thesubstance through the solvent, the first conveyor including an upper endand a lower end opposite its upper end, wherein the first conveyincludes an inclined first upper surface and an inclined first lowersolid surface substantially parallel to the inclined first uppersurface; wherein the first conveyor is configured to move the substancedownward through the solvent along the first upper surface toward thelower end and upward through the solvent along the first lower solidsurface toward the upper end, wherein the compound comprises rubber andthe solid or semisolid substance comprises guayule plant matter.
 2. Theextractor of claim 1, wherein the solvent flows from the solvent inletto the solvent outlet in a direction generally counter to the movementof the substance from the substance inlet to the substance outlet. 3.The extractor of claim 1, further comprising: a second conveyingassembly including: a second inclined conveyor positioned between thefirst conveyor and the substance outlet and substantially parallel tothe first conveyor, the second conveyor including an upper end and alower end opposite its upper end, wherein the second conveyor includesan inclined second upper surface and an inclined second lower solidsurface substantially parallel to the inclined second upper surface;wherein the second conveyor is configured to move the substance downwardthrough the solvent along the second upper surface toward the secondconveyor lower end and upward through the solvent along the second lowersolid surface toward the second conveyor upper end.
 4. The extractor ofclaim 3, wherein the first lower surface includes an upper terminal endpositioned above the second conveyor such that substance falls from thefirst lower solid surface toward the second upper surface when movedbeyond the upper terminal end by the first conveyor.
 5. The extractor ofclaim 1, further comprising a tank configured to contain solvent at apredetermined level within the extractor, wherein the upper terminal endof the first lower solid surface is positioned at or below the level ofsolvent in the extractor.
 6. The extractor of claim 1, wherein the firstconveyor is inclined at an angle in the range of approximately 20degrees to approximately 30 degrees.
 7. The extractor of claim 1,further comprising: an exit conveying assembly including: an exitconveyor positioned between the first conveyor and the substance outletand substantially parallel to the first conveyor, the exit conveyorincluding an upper end and a lower end opposite its upper end, whereinthe exit conveyor includes an inclined exit upper surface and aninclined exit lower surface substantially parallel with the inclinedexit upper surface; wherein the exit conveyor is configured to move thesubstance downward through the solvent along the exit upper surfacetoward the exit conveyor lower end and upward through the solvent alongthe exit lower surface toward the exit conveyor upper end.
 8. Theextractor of claim 7, wherein the exit conveyor has a length that isapproximately 175% to approximately 200% the length of the firstconveyor.
 9. The extractor of claim 7, wherein the inclined exit lowersurface at least partially comprises an inclined screen section, whereinthe exit conveyor is configured to move the substance from the inclinedexit lower surface upward along the inclined screen section toward theinclined exit conveyor upper end, wherein the inclined screen section isconfigured to allow solvent to drain from the substance.
 10. Theextractor of claim 9, wherein a solvent inlet is configured to spraysolvent onto the inclined screen section.
 11. The extractor of claim 9,wherein the inclined screen section comprises approximately 40% toapproximately 55% the length of the exit conveyor.
 12. A method ofseparating a compound from a solid or semi-solid substance using theextractor of claim 9 and at least one solvent, the method comprising:introducing the substance into a pool of at least one solvent capable ofdissolving the compound; conveying the substance downward along thefirst inclined surface through the pool of the solvent; conveying thesubstance upward along the second inclined solid surface through thepool of solvent; and conveying the substance upward along the inclinedscreen to separate the solvent from the substance.
 13. The method ofclaim 12, wherein prior to the conveying the substance upward along theinclined screen, the method further comprises: moving the substance fromthe upper end of the second inclined solid surface to a third inclinedsurface; conveying the substance downward along the third inclinedsurface through the pool of the solvent; and conveying the substanceupward along a fourth inclined solid surface through the pool ofsolvent.
 14. The method of claim 12, further comprising at least one ofthe following: a. introducing solvent into the pool of solvent byspraying solvent over the inclined screen; b. keeping the substancesubstantially constantly immersed in the solvent after introducing thesubstance into the pool of solvent and before conveying the substanceupward along the inclined screen; or c. flowing the solvent in adirection substantially counter to the direction of conveying thesubstance upward along the second inclined solid surface.
 15. Theextractor of claim 1, further comprising a clarifying conveyor and aninclined clarifying lower surface associated with the clarifyingconveyor, wherein the clarifying conveyor is positioned between thesubstance inlet and the solvent outlet and is configured to move thesubstance upward through the solvent along the clarifying lower surfacetoward the first conveyor.
 16. The extractor of claim 1, furthercomprising a separator in fluid communication with the solvent outlet,the separator configured to separate small particles of substance fromthe solvent that exits the solvent outlet.
 17. The extractor of claim 1,wherein the substance outlet includes a run-down screen configured toreceive solvent-containing substance from the exit conveyor and allow atleast a portion of the solvent to drain from the solvent-laden substancewhile on the screen; wherein the run-down screen has no moving parts andremoval of the substance from the run-down screen is gravity fed. 18.The extractor of claim 1, wherein each conveyor includes paddlesconfigured to assist in moving the substance along the upper and lowersurfaces associated with each respective conveyor.
 19. The extractor ofclaim 1, further comprising at least one additional solvent inlet,solvent outlet, substance inlet, or substance outlet.
 20. The extractorof claim 1, wherein the extractor comprises additional conveyingassemblies for moving the substance through the solvent such that theextractor has a total of six conveying assemblies arranged in series,each additional conveying assembly including an inclined conveyor, aninclined upper surface and an inclined lower solid surface substantiallyparallel with the inclined upper surface.
 21. An extractor suitable forusing a solvent to separate a compound from a solid or semisolidsubstance containing the compound, comprising: a substance inlet forintroducing the substance into the extractor; a substance outlet forremoving the substance from the extractor; a solvent inlet forintroducing the solvent into the extractor; a solvent outlet forremoving the solvent from the extractor; and a first conveying assemblyincluding: an inclined first conveyor for receiving the substance fromthe substance inlet and moving the substance through the solvent, thefirst conveyor including an upper end and a lower end opposite its upperend, wherein the inclined first conveyor includes an inclined firstupper surface and an inclined first lower solid surface substantiallyparallel with the inclined first upper surface; wherein the firstconveyor is configured to move the substance downward through thesolvent along the first upper surface toward the lower end and upwardthrough the solvent along the first lower solid surface toward the upperend, a second conveying assembly including: a second inclined conveyorpositioned between the first conveyor and the substance outlet andsubstantially parallel to the first conveyor, the second conveyorincluding an upper end and a lower end opposite its upper end, whereinthe second inclined conveyor includes an inclined second upper surfaceand an inclined second lower solid surface; wherein the second conveyoris configured to move the substance downward through the solvent alongthe second upper surface toward the second conveyor lower end and upwardthrough the solvent along the second lower solid surface toward thesecond conveyor upper end; and an exit conveying assembly including: anexit conveyor positioned between the first conveyor and the substanceoutlet and substantially parallel to the first conveyor, the exitconveyor including an upper end and a lower end opposite its upper end,wherein the exit conveyor includes an inclined exit upper surface and aninclined exit lower surface substantially parallel to the inclined exitupper surface; wherein the exit conveyor is configured to move thesubstance downward through the solvent along the exit upper surfacetoward the exit conveyor lower end and upward through the solvent alongthe exit lower surface toward the exit conveyor upper end wherein thecompound comprises rubber and the solid or semisolid substance comprisesguayule biomass.